I am getting "UNC" errors on a hard disk on Ubuntu 9.10. It slows down my system, applications have not been responding for a long time. But when I mount the filesystem on another computer, it works properly.

disk: SAMSUNG HD161HJ (SATA)

syslog:

Apr 25 00:28:25 vare6gin kernel: [  885.773839] ata3.00: exception Emask 0x1 SAct 0x1e 
SErr 0x0 action 0x6 frozen
Apr 25 00:28:25 vare6gin kernel: [  885.773845] ata3.00: Ata error. fis:0x21
Apr 25 00:28:25 vare6gin kernel: [  885.773861] ata3.00: cmd 60/08:08:3f:00:ad/00:00:10:00:00/40 tag 1 ncq 4096 in
Apr 25 00:28:25 vare6gin kernel: [  885.773864]          res 51/40:24:67:c8:91/40:00:05:00:00/40 Emask 0x9 (media error)
Apr 25 00:28:25 vare6gin kernel: [  885.773871] ata3.00: status: { DRDY ERR }
Apr 25 00:28:25 vare6gin kernel: [  885.773877] ata3.00: error: { UNC }

[...snip 3 similar repeats of last 4 lines; see revision history for full log...]

Apr 25 00:28:25 vare6gin kernel: [  885.773970] ata3: hard resetting link
Apr 25 00:28:25 vare6gin kernel: [  885.773974] ata3: nv: skipping hardreset on occupied port
Apr 25 00:28:25 vare6gin kernel: [  886.240073] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Apr 25 00:28:25 vare6gin kernel: [  886.256277] ata3.00: configured for UDMA/133
Apr 25 00:28:25 vare6gin kernel: [  886.256305] ata3: EH complete
Apr 25 00:28:27 vare6gin kernel: [  888.176088] ata3: EH in SWNCQ mode,QC:qc_active 0xF sactive 0xF
Apr 25 00:28:27 vare6gin kernel: [  888.176099] ata3: SWNCQ:qc_active 0xF defer_bits 0x0 last_issue_tag 0x3
Apr 25 00:28:27 vare6gin kernel: [  888.176102]   dhfis 0xF dmafis 0x1 sdbfis 0x0
Apr 25 00:28:27 vare6gin kernel: [  888.176109] ata3: ATA_REG 0x51 ERR_REG 0x40
Apr 25 00:28:27 vare6gin kernel: [  888.176113] ata3: tag : dhfis dmafis sdbfis sacitve
Apr 25 00:28:27 vare6gin kernel: [  888.176120] ata3: tag 0x0: 1 1 0 1  
Apr 25 00:28:27 vare6gin kernel: [  888.176126] ata3: tag 0x1: 1 0 0 1  
Apr 25 00:28:27 vare6gin kernel: [  888.176131] ata3: tag 0x2: 1 0 0 1  
Apr 25 00:28:27 vare6gin kernel: [  888.176136] ata3: tag 0x3: 1 0 0 1